DE3942668A1 - POLYMER COMPOSITIONS AND METHOD FOR THE PRODUCTION THEREOF - Google Patents

Abstract

Block polymer compositions comprise: (a) a linear copolymer constituted by four alternating blocks, represented by formula (I) or (II> B1-T-A1-B2-A2 (I> or B1-A1-B2-T-A2 (II> wherein: B1 and B2 are polydienic preferably polybutadienic blocks; A1 and A2 are polyvinylaromatic, preferably polystyrenic blocks; T is a portion of random copolymer formed by dienic and vinylaromatic monomer units; (b) a linear copolymer consitituted by two blocks, represented by formulae (III) or (IV> B3-T-A3 (III> or B3-A3 wherein: B3 is a polydienic block; A3 is a polyvinylaromatic block; and T has the above meaning. The polymeric composition, which can be blended with polystyrene, can be obtained both by blending the individual components, and by means of novel and original synthesis processes which make it possible both (A) and (B) components to be obtained simultaneously. The compositions have good impact strength, transparence and processability.

Description

The present invention relates to polymer compositions, full

a linear copolymer consisting of four alternating Blocks represented by the formula (I) or (II) can be represented:

B₁ - T - A₁ - B₂ - A₂ (I)

or

B₁ - A₁ - B₂ - T - A₂ (II)

wherein A₁, A₂, B₁, B₂ and T are each 2 vinyl aromatic blocks, 2 diene blocks and a part of a static copolymer formed from dienic and vinyl aromatic monomer units; and
a copolymer consisting of two blocks, which can be represented by the formulas (III) or (IV):

B₃ - T - A₃ (III)

or

B₃ - A₃ (IV)

wherein A₃ is a polyvinyl aromatic block, different from or equal to the block A₁ or A₂; B₃ is a polydienic Block is different from or equal to the block B₁ or B₂, and T is the above random copolymer means.

Also, the method for producing both of the above components this mixture at the same time and during the same Synthetic processes fall within the scope of the present Invention.

The polymer compositions are very good in impact resistance. and processing properties, combined equipped with high clarity, what they are for all uses for transparent, impact resistant Makes materials suitable.

Over the past few years, the block copolymers have that of the block copolymerization of conjugated dienischen monomers with vinyl aromatic monomers be such. B. the block copolymers of polybutadiene and polystyrene and the block copolymers of Polyisoprene with polystyrene, a special development experience. Such copolymers can be used as such be, d. H. in the same form as through living-anionic Copolymerization are generated, as well as after their partial or total hydrogenation.

This is the case for linear block copolymers made up of alternating blocks of polydienes and polyvinyl arenes  exist, with a special structure and distribution of individual blocks and with a structural formula of the type (I) or (II), which is an extremely favorable Balance of physical and mechanical Show properties. Such block copolymers and their Derivatives are from the applicant in the DOS P 37 37 439.7 and in the German patent application P 39 38 927.8 described.

The mixing of block copolymers with each other as well as with impact-resistant and non-impact polystyrene, to achieve resins with improved properties, is also known from the prior art.

Compositions and / or block copolymers obtained by characterized the use of polymeric structures are suitable for all purposes, for the transparent, Impact-resistant polystyrene used in the past was or is still used, for example in GB-PS 11 30 770, GB-PS 13 35 077 and US-PS 40 86 298 described.

However, those described in these publications and claimed copolymers not optimal Balance of rheological properties, impact resistance and transparency.

Such a balance of properties will further changed by the possible use of polystyrene, on the one hand improves the optical properties, on the other hand, the impact resistance of the thus obtained Compositions reduced.

The disadvantages which affect the prior art, are determined by the polymer compositions according to overcome the present invention consisting of mixtures consist of two block copolymers, the above mentioned, general formulas (I) or (II) and (III) and (IV).

According to a first aspect of the present invention these novel polymer compositions comprising

• (a) 40 to 90% by weight of a block copolymer of general formula (I) or (II);
• (b) 10 to 60% by weight of a block copolymer of general formula (III) or (IV),

wherein the symbols A₁, A₂, A₃, B₁, B₂, B₃ and T are as indicated above Have meaning.

The polymer compositions of the present invention are characterized in that the weight average Molecular weight of the four-block copolymer of Formula (I) or (II) in the range of 50,000 to 300,000 while the weight average molecular weight of the two-block copolymer in the range of 20,000 to 150,000.

In the same compositions is the weight percentage of the statistical block T in the range of 5 to 50%, preferably from 10 to 25%, based on the Entity of the two copolymers containing the mixture form.

In the same compositions is the total amount vinyl aromatic monomer units in the range from 60 to 90 wt .-%, with the balance to 100% by the dienic monomer units is formed.  

In the above definitions, the blocks A₁, A₂, A₃ and B₁, B₂ and B₃ are practically pure blocks; d. H. you are almost completely by vinylarenische and dienische Formed units.

In the preferred form of practical implementation are the blocks B₁, B₂ and B₃ polystyrene blocks and T is a styrene-butadiene random copolymer.

Furthermore, in the preferred form of practical Carrying out the total content of serving units in the polymer composition in the range of 20 to 30 wt .-% and the weight average molecular weight of Four block copolymers is in the range of 100,000 up to 200,000; the weight average molecular weight of Two-block copolymers are in the range of 40,000 to 100,000. These compositions may be another Polystyrene resin, such as. As polystyrene or impact Polystyrene, be added in such an amount that the Combination of the characteristics of the binary composition is not endangered.

The polymer compositions according to the invention form a progress from the point of view of the properties, compared with the block copolymer of formula (I) or (II) if considered as an individual basis.

The linear block copolymer passing through the 4 alternating Blocks is formed and the general formula (I) or (II) according to the invention can, by Be obtained by polymerization in an organic Solvent is used, if necessary in suitable amounts an aliphatic or cycloaliphatic,  polar compound is added, selected under ethers or amines, at temperatures in the range from 30 to 150 ° C and under pressures equal or higher than atmospheric pressure in the presence of alkyl Metal or aryl-metal initiators, as they usually do in the synthesis of polymers according to the living anionic Polymerization method can be used.

Such a synthetic route is described in DOS P 37 37 439.7, which such copolymers and a method concerning their production. The two-block copolymers The above formulas (III) or (IV) can be used in In contrast, be prepared by known methods or by the same synthetic method as it described in the above DOS, wherein the reaction limited to the first step. In particular be used for the synthesis of the copolymers of the formula (III) measured amounts of butadiene and styrene in a reactor fed as a mixture with each other and the polymerization in solution in a hydrocarbon with a suitable initiator for anionic living polymerization carried out until the monomer conversion is complete or substantially complete; to this Weise becomes a living two-block copolymer

B₃ - T - A₃

formed of non-pure blocks, d. H. out Blocks linked together by a copolymer chain part connected from statistically bound Monomer units of butadiene and styrene is formed.

The polymer formed becomes after preliminary elimination of living, active centers by adding won a compound with an acidic character.  

The recovery of the polymer material is customary Methods performed, such. B. evaporation of the solvent and drying the polymer.

The copolymer of formula (IV) is characterized by anionic Polymerization with successive addition of the monomers obtained by known methods.

The components of the polymer compositions according to the Invention can be mixed together and compounded according to known from the prior art modalities and ways. So z. B. the ingredients in molten Condition mixed and extruded or be mixed in a Banbury-type mixer or they can be mixed as solutions. There were too new and original methods developed, giving another Aspect and purpose of the present invention whereby it is possible to make the two Components simultaneously and by means of a single Synthesis process produce.

According to such a method, the synthesis is carried out the following steps are performed:

• (1) a first step during which a mixture is copolymerized in the presence of initiators until the conversion of the monomers is approximately complete, this mixture consisting of a vinyl aromatic monomer and a conjugated dienic monomer in an apolar solvent selected from the solvents wherein polystyrene having a weight-average molecular weight in the range of 30,000 to 120,000 is soluble at concentrations of 5 to 20% by weight. The initiators are alkyl lithium compounds to provide a living polymer system. The solvent system may contain polar compounds, such as ethers, amines and the like, at a maximum concentration of 0.1% by weight, based on the solvent.
  The weight percentage of the monomers introduced into the mixture for the first reaction step according to the invention is in the range from 30 to 60% by weight, based on all the monomers fed to the reaction. During the above reaction, a living copolymer of the B₁-T-A₁ type is formed.
• (2) A second step wherein a percentage of the living active sites formed during the first reaction step is suppressed by adding compounds to the system characterized by containing acidic hydrogen atoms (H₂O, alcohols and the like). ) in their chemical structure.
  The amount of active site deactivating agents to be fed to the second step of such a process is in the range of 10 to 50 mole percent, based on the moles of initiator added in the first step.
• (3) A third step, wherein a conjugated Served to the living system of the second step and a complete transformation is received.  
• (4) A fourth step, wherein a vinyl aromatic Monomeres fed and almost completely converted.
• (5) A fifth step, wherein the living, active Centers are completely suppressed by a compound is added with acidic reaction.

In this way, the mixture of the two copolymers

B₁ - T - A₁ - B₂ - A₂ + B₁ - T - A₁

receive.

This procedure is generalized above Conditions of temperature and pressure carried out d. H. at temperatures in the range of 30 to 150 ° C and under atmospheric or superatmospheric Print.

One of the variants, which alternative ways for the above described method comprises at the end of the first Polymerization stage of the mixture of monomers a second step, wherein a second aliquot of the Initiator is added. Such a path leads to education an additional number of active centers which are pure block copolymers, previously by means of the formula

B₃ - T - A₃

have been described.

In this case, the different, consecutive Steps as follows:  

• (1) synthesis of a pure diene block;
• (2) Synthesis of a pure vinyl aromatic Blocks in the sequence of the Diener block;
• (3) adding a further aliquot of initiator;
• (4) feeding a mixture consisting of a dienic monomers and a vinylaromatic monomer. The amount of monomers introduced in mixture with each other are in the range of 30 to 60% to all monomers that are fed to the reaction.
• (5) elimination of living, active centers by means of a compound containing acidic hydrogen atoms.

By methods analogous to those described above are described, can be two polymer blends to be obtained:

B₁ - A₁ - B₂ - T - A₂ + B₁ - A₁

or

B₁ - T - A₁ - B₂ - A₂ + B₂ - A₂.

The preferred initiators for the intended purpose are those that belong to the group, consisting of both linear as well as branched alkyllithium compounds and below, n-butyl lithium and sec-butyl lithium.

These initiators are commonly used in the various Steps of the procedure used in quantities that in the range of 0.025 to 0.2 parts by weight / 100 parts each of the monomers subjected to the polymerization.

The appropriate solvents for the intended purpose are apolar solvents and among these are those in which  the polyvinyl aromatic blocks with a weight average Molecular weight in the range of 50,000 to 200 000 are soluble; among the most suitable cyclohexane and benzene can be mentioned.

These solvents can be polar compounds, such as Ethers, amines and the like., Contain their presence also next to an increase in the speed of Polymerization reaction of the various steps one Increase in the weight of the random copolymer part T causes. Among them, tetrahydrofuran is preferable.

The following embodiments illustrate the invention, without limiting it in any way.

Example 1

600 g of anhydrous cyclohexane, 55 g of styrene (99.9% pure) and 13 g of butadiene (99.85% pure) are added to a reactor of 1000 ccm fed with stirring; the temperature of the mass is increased up to 50 ° C and 0.055 g sec-butyllithium (in solution in n-hexane) are added.

25 minutes later, the reaction mass reaches the temperature of 75 ° C and the conversion of the monomers is practical Completed. Then the system is 0.009 g of pure methanol and then added 7 g of butadiene. To 10 min, the reaction mass reaches the temperature of 85 ° C and the conversion of butadiene is practical Completed.

Finally, 25 grams of styrene are added and 15 minutes later the conversion is practically complete, with the  Temperature of the reaction mass reaches a value of 90 ° C. Has.

Switching off the living, active centers is through Added 0.5 cc of water to the polymer solution.

1.0 g of triphenyl nonyl phosphite and 0.2 g of [pentaerythritol] tetra (3,5-di-tert-butyl-4-hydroxyphenyl-propionate)] are added to the polymer solution.

The recovery of the polymer mixture is by steam distillation the reaction solvent and then Dry in a vacuum oven at 60 ° C for 24 h.

The physical properties of the two components the polymer blend are given in Table 1. The mechanical and optical properties at 180 ° C pressed samples are listed in Table 2.

Table 1

analysis GPC (Gel Permeation Chromatography) | (1) IR analysis (2) Abort with OsO₄ (3) 200 ° C, 5 kg (4)

Table 2 Transparency,% 92 Tensile strength, kg / cm² 230 Elongation at break,% 35 Module, kg / cm² 8000 Notched Izod impact test at 23 ° C, kg x cm / cm 2.5

example 2

850 g of anhydrous cyclohexane, 37.5 g of styrene and 12.5 g Butadiene is fed to a stirred reactor of 2000 cc; the temperature of the system is up to 55 ° C increased, and 0.040 g of n-butyllithium (in solution in n-hexane) are added.

45 minutes later, the reaction mass reaches the temperature of 68 ° C and the conversion of the monomers is convenient Completed.

Then, the reaction solution is 0.032 g of n-butyllithium and then added 37.5 g of butadiene; reached after 20 minutes the reaction mass the temperature of 78 ° C and the conversion is practically complete.

112.5 g of styrene are then added to the polymer solution and 60 minutes later is the conversion of the monomer Completed.

The reaction is then added by addition of 2 g of methanol the solution containing the polymer mixture is suppressed. The addition of the antioxidant and the recovery and drying of the polymer are prepared in the same manner as in Example 1 performed.  

The physical properties of the two components the polymer blend are given in Table 3. The mechanical and optical properties at 180 ° C pressed samples are summarized in Table 4.

Table 3

Table 4 Transparency,% 86 Tensile strength, kg / cm² 165 Elongation at break,% 100 Module, kg / cm² 7000 Notched Izod Impact, specimen at 23 ° C, kg x cm / cm 3.2

example 3

1.2 kg of cyclohexane, 0.3 g of tetrahydrofuran, 100 g of styrene and 45 g of butadiene are placed in a reactor with a capacity of 1.5 l introduced; the temperature of the mass rises to 50 ° C, and 0.12 g of n-butyllithium (in solution in n-hexane) are added.

30 minutes later, the reaction mass reaches the temperature of 80 ° C, and the conversion of the monomers is practical Completed.

Then 0.012 g of water and then 15 g of butadiene added to the system. Reached 10 minutes later the reaction mass the temperature of 90 ° C, and the conversion of butadiene is complete.  

Finally, 40 g of styrene are added and after 15 min Reaction, the transformation is complete.

Before the solid polymer is recovered, the living, active centers by adding 2 g of isopropyl alcohol suppressed to the system. After adding the antioxidant as in Example 1, the extraction of the solid Polymers by steam distillation of the solvent and then drying the solid residue carried out at 65 ° C for 24 h.

The physico-chemical properties are in table 5 listed.

Table 5

example 4

5 kg of the mixture of Example 3 are commercially available with 5 kg crystalline polystyrene [MG (GPC) = 250 × 10³] mixed. This mass is a twin-screw extruder, equipped with a heating jacket, fed. This procedure is repeated twice to get an optimal one To achieve mixing. The material is then in Granules of 0.5 cm in length transferred.

The properties of the compound thus prepared are are determined at 180 ° C compressed samples and are in Table 6 listed.

Table 6 MFI, g / 10 min 8.2 Transparency,% 90 Tensile strength, kg / cm² 185 Elongation at break,% 100 Module, kg / cm² 12,000 Notched Izod Impact, kg x cm / cm 3.5

example 5

600 g of anhydrous cyclohexane and 30 g of butadiene (99.84% pure) are placed in a 1 liter reactor; the mass is heated to 60 ° C and with 0.09 g of sec-butyllithium added.

20 minutes later, the polymerization of butadiene is complete and the reaction temperature is about 60 ° C.

70 g of styrene (99.9% pure) are then added to the system, and the reaction is complete within 20 min. During this time, the reaction mass reaches the temperature from 82 ° C.

To the reaction mass is added 0.058 g of initiator (n-butyllithium) and then from 70 g of styrene and 30 g of butadiene existing reaction mixture.

The reaction takes place within 25 minutes and the final reaction temperature is 102 ° C. At the end of the procedure 3 g of methyl alcohol are added to the system to to suppress the active centers.

To the polymer solution is added 0.8 g of TNPP (triphenylnonyl phosphite) and 0.15 g of pentaerythritol tetraalkyl- (3,5-di-  tert-butyl-4-hydroxyphenyl) propionate. The Polymers are made by steam distillation of the solvent won, and the recovered polymer is then dried in a vacuum oven at 60 ° C for 36 h.

The physico-chemical properties and mechanical Properties of the polymer mixture are in the Tables 7 and 8 indicated.

Table 7

Table 8 Transparency,% 85 Elongation at break,% 125 Tensile strength, kg / cm² 1.10 Module, kg / cm² 6800 Notched Izod Impact, specimen at 23 ° C, kg x cm / cm 5.0

Claims (14)

A polymer composition comprising

• (a) 40 to 90% by weight of a linear copolymer of four alternating blocks which can be represented by the formula B₁-T-A₁-B₂-A₂ (I) or B₁-A₁-B₂-T-A₂ (II) wherein
  A₁ and A₂ are polyvinyl aromatic blocks;
  B₁ and B₂ are polydiene blocks;
  T is a copolymer chain member formed by random, diene and vinyl aromatic monomer units;
• (B) 10 to 60 wt .-% of a linear copolymer of two blocks, which is represented by either the formula B₃ - T - A₃ (III) wherein
  A₃ is a polyvinylaromatic block, either the same or different from the block A₁ or block A₂;
  B₃ is a polydiene block, either the same or different from block B₁ or B₂;
  T has the meaning given above, or, alternatively, may be represented by the formula B₃ - A₃ (IV).

2. Polymer composition according to claim 1, characterized characterized in that the linear four-block polymer (I) or (II) a weight average molecular weight in the Range from 50,000 to 300,000.   3. Polymer composition according to claim 1 and 2, characterized in that the weight average molecular weight represented by the formula (III) or (IV) Polymers in the range of 20,000 to 150 000 lies. 4. Polymer composition according to the preceding Claims, characterized in that in this composition the total amount of vinyl aromatic monomer units in the range of 60 to 90% by weight, while balancing to 100% by dienic monomer units is formed. 5. Polymer composition according to the preceding Claims, characterized in that the dienischen Blocks are polybutadiene blocks and the polyvinylaromatic ones Blocks are polystyrene blocks. 6. Polymer composition according to the preceding Claims, characterized in that the individual Components are mixed to the same composition display. 7. A process for preparing a polymer composition according to the preceding claims, characterized in that
in a first step, metered amounts of a diene and a vinyl aromatic monomer interpolymerized by anionic living polymerization until complete or near complete monomer conversion;
in a second step, suppressing a percentage in the range of 10 to 60% of the active living centers produced by the first reaction step, partly by addition of compounds having acidic hydrogen atoms;
adding a measured amount of the diene to the bulk of the second step and polymerizing in a third step by anionic living polymerization until the conversion of the added diene is complete or substantially complete;
adding a measured amount of the vinyl aromatic monomer to the product coming from the third step and polymerizing in a fourth step until the conversion of the charged vinyl aromatic monomer is complete or substantially complete;
the mixture of the polymers from the fourth stage polymerization products after previously completely eliminating the living active sites by a compound having acidic hydrogen atoms, thus obtaining the polymer mixture consisting of two polymers B₁-T-A₁-B₂-A₂ + B₁ - T - A₁ receives. 8. A process for preparing a polymer composition according to claims 1 to 5, characterized in that
in a first step, polymerizing metered amounts of conjugated diene by anionic living polymerization until the monomer conversion is complete or nearly complete;
in a second step, adding and polymerizing a measured amount of a vinyl aromatic monomer to the reaction mass from the first step until the conversion of the added vinyl aromatic monomer is complete or substantially complete;
in a third step, the partial elimination of a percentage in the range of 10 to 60% of the active sites formed in the preceding stages by the addition of compounds having acidic hydrogen atoms;
in a fourth step, adding a mixture consisting of measured amounts of a diene and a vinyl aromatic monomer and continuing the polymerization until the conversion of these monomers is complete or nearly complete;
the prepared mixture of the polymer coming from the fourth stage after previously switching off the living, active centers by a compound containing acidic hydrogen atoms, and in this way the polymer mixture consisting of the polymers B₁ - A₁ - B₂ - T - A₂ + B₁ - A₁, is obtained. 9. A process for preparing a polymer composition according to claims 1 to 5, characterized in that
in a first step, polymerizing metered amounts of a conjugated diene by anionic living polymerization until the monomer conversion is complete or nearly complete;
in a second step, adding and polymerizing a measured amount of a vinyl aromatic monomer of the reaction mass from the first stage until the conversion of the added vinyl aromatic monomer is complete or substantially complete;
in a third step, adding another aliquot of the anionic polymerization initiator;
in a fourth step, metered amounts of a diene and a vinyl aromatic monomer in admixture with each other and in amounts ranging from 30 to 60% based on the monomers added to the process and polymerization continues until the conversion of the monomers is complete or nearly complete is;
the copolymer of the polymerization products coming from the fourth step, after previously switching off the living active sites by addition of a compound containing acidic hydrogen atoms, and in this way, the polymer mixture consisting of the two polymers B₁ - A₁ - B₂ - T - A₂ + B₂ - T - A₂, is obtained. 10. A process for preparing a polymer composition according to claims 1 to 5, characterized in that
in a first step, metered amounts of a conjugated diene and a vinyl aromatic monomer are polymerized in admixture with each other by anionic living polymerization until complete or near complete monomer conversion;
in a second step, adding another aliquot of the anionic living polymerization initiator;
in a third step, adding a measured amount of a conjugated diene and continuing the polymerization until the conversion of the monomer is complete or nearly complete;
in a fourth step, supplying a measured amount of a vinyl aromatic monomer and continuing the polymerization until complete conversion of the monomer is obtained;
the mixture of the polymers produced and coming from the fourth step after complete elimination of the living, active centers with a compound containing acidic hydrogen atoms, wins and in this way a polymer mixture consisting of the two polymers B₁ - T - A₁ - B₂ - A₂ + B₂ - A₂, is obtained. 11. The method according to claims 7, 8, 9, 10, characterized characterized in that the polymerization is carried out is by adding in an organic, aliphatic or cycloaliphatic solvents at temperatures in the range of 30 to 150 ° C and under pressure equal to or higher than atmospheric pressure in the presence an alkyl metal or aryl metal is worked. 12. The method according to claim 11, characterized that the polymerization in the presence of at least one linear or cyclic, polar compound, selected among the ethers or amines, in quantities in the Range of 0.01 to 0.1 parts by weight, based on the Solvent can be performed. 13. The method according to claims 7, 8, 9, 10, characterized characterized in that the solvent is cyclohexane and the reaction temperature is in the range of 50  to 100 ° C, the initiator is an alkyllithium containing 3 to 7 carbon atoms in the alkyl group and the initiator in amounts ranging from 0.025 to 0.20 parts by weight for each 100 parts by weight of vinyl aromatic Monomer is used. 14. The method according to claims 7, 8, 9, 10, characterized characterized in that the diene is butadiene and the vinyl aromatic compound is styrene.